Most modern automotive fuel systems utilize fuel injectors to provide precise metering of fuel for introduction towards each combustion chamber. Additionally, the fuel injector atomizes the fuel during injection, breaking the fuel into a large number of very small particles, increasing the surface area of the fuel being injected, and allowing the oxidizer, typically ambient air, to more thoroughly mix with the fuel prior to combustion. The metering and atomization of the fuel reduces combustion emissions and increases the fuel efficiency of the engine. Thus, as a general rule, the greater the precision in metering and targeting of the fuel and the greater the atomization of the fuel, the lower the emissions with greater fuel efficiency.
An electromagnetic fuel injector typically utilizes a solenoid assembly to supply an actuating force to a fuel metering assembly. Typically, the fuel metering assembly is a plunger-style closure member which reciprocates between a closed position, where the closure member is seated in a seat to prevent fuel from escaping through a metering orifice into the combustion chamber, and an open position, where the closure member is lifted from the seat, allowing fuel to discharge through the metering orifice for introduction into the combustion chamber.
The fuel injector is typically mounted upstream of the intake valve in the intake manifold or proximate a cylinder head. As the intake valve opens on an intake port of the cylinder, fuel is sprayed towards the intake port. In one situation, it may be desirable to target the fuel spray at the intake valve head or stem while in another situation, it may be desirable to target the fuel spray at the intake port instead of at the intake valve. In both situations, the targeting of the fuel spray can be affected by the spray or cone pattern. Where the cone pattern has a large divergent cone shape, the fuel sprayed may impact on a surface of the intake port rather than towards its intended target. Conversely, where the cone pattern has a narrow divergence, the fuel may not atomize and may even recombine into a liquid stream. In either case, incomplete combustion may result, leading to an increase in undesirable exhaust emissions.
Complicating the requirements for targeting and spray pattern is cylinder head configuration, intake geometry and intake port specific to each engine""s design. As a result, a fuel injector designed for a specified cone pattern and targeting of the fuel spray may work extremely well in one type of engine configuration but may present emissions and driveability issues upon installation in a different type of engine configuration. Additionally, as more and more vehicles are produced using various configurations of engines (for example: inline-4, inline-6, V-6, V-8, V-12, W-8 etc.,), emission standards have become stricter, leading to tighter metering, spray targeting and spray or cone pattern requirements of the fuel injector for each engine configuration.
It would be beneficial to develop a fuel injector in which increased atomization and precise targeting can be changed so as to meet a particular fuel targeting and cone pattern from one type of engine configuration to another type.
It would also be beneficial to develop a fuel injector in which non-angled metering orifices can be used in controlling atomization, spray targeting and spray distribution of fuel towards an arcuate sector about the longitudinal axis for a predetermined distance downstream from the fuel injector.
The present invention provides fuel targeting and fuel spray distribution with non-angled metering orifices. In particular, the preferred embodiments of the invention allow for targeting of fuel flow to an arcuate sector about the longitudinal axis. In a preferred embodiment, a fuel injector is provided. The fuel injector includes a housing, a seat, a closure member and a metering disc. The housing has passageway extending between an inlet and an outlet along a longitudinal axis. The seat has a sealing surface facing the inlet and forming a seat orifice with a terminal seat surface spaced from the sealing surface and facing the outlet, and a first channel surface generally oblique to the longitudinal axis and is disposed between the seat orifice and the terminal seat surface. The closure member is disposed in the passageway and contiguous to the sealing surface so as to generally preclude fuel flow through the seat orifice in one position. The closure member is coupled to a magnetic actuator that, when energized, positions the closure member away from the sealing surface of the seat so as to allow fuel flow through the passageway and past the closure member. The metering disc is contiguous to the seat and includes a second channel surface confronting the first channel surface so as to form a flow channel. The metering disc has at least one metering orifice located outside of the first virtual circle. Each metering orifice extends generally parallel to the longitudinal axis between the second channel surface and a outer surface spaced from the second channel surface. The at least one metering orifice is located on one quadrant defined by two perpendicular planes parallel to and intersecting the longitudinal axis of the metering disc so that when the closure member is in the actuated position, a flow of fuel through the at least one metering orifice is targeted within an arcuate sector of at least 90 degrees about the longitudinal axis.
In yet another aspect of the present invention, a method targeting fuel flow to a desired sector downstream of a fuel injector about a longitudinal axis is provided. The fuel injector includes a passageway extending between an inlet and outlet along a longitudinal axis, a seat and a metering disc. The seat has a sealing surface facing the inlet and forming a seat orifice. The seat has a terminal seat surface spaced from the sealing surface and facing the outlet, and a first channel surface generally oblique to the longitudinal axis and disposed between the seat orifice and the terminal seat surface. The closure member is disposed in the passageway and contiguous to the sealing surface so as to generally preclude fuel flow through the seat orifice in one position. The closure member is coupled to a magnetic actuator that, when energized, positions the closure member away from the sealing surface of the seat so as to allow fuel flow through the passageway and past the closure member. The metering disc has at least one metering orifice extending between second and outer surfaces along the longitudinal axis with the second surface facing the first channel surface. The method can be achieved, in part, by locating the metering orifices outside of the first virtual circle and on at least one quadrant defined by two perpendicular planes parallel to and intersecting a longitudinal axis of the metering disc, the metering orifices extending generally parallel to the longitudinal axis through the second and outer surfaces of the metering disc; and targeting a flow of fuel through the at least one metering orifices within an arcuate sector of at least 90 degrees about the longitudinal axis upon actuation of the fuel injector.